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Enterotoxigenic Escherichia coli (ETEC) is a common cause of diarrheal illness in the military, travelers, and children living in low- to middle-income countries. Increased antibiotic resistance, the absence of a licensed vaccine, and the lack of broadly practical therapeutics perpetuate the significant health and financial burden resulting from ETEC infection. A critical step in the evaluation of vaccines and therapeutics is preclinical screening in a relevant animal disease model that closely replicates human disease. We previously developed a diarrheal model of class 5a colonization factor (CF) CFA/I-expressing ETEC in the New World owl monkey species Aotus nancymaae using ETEC strain {"type":"entrez-nucleotide","attrs":{"text":"H10407","term_id":"875229","term_text":"H10407"}}H10407. In order to broaden the use of the model, we report here on the development of A. nancymaae models of ETEC expressing the class 5b CFs CS17 and CS19 with strains LSN03-016011/A and WS0115A, respectively. For both models, we observed diarrheal attack rates of ≥80% after oral inoculation with 5 × 1011 CFU of bacteria. These models will aid in assessing the efficacy of future ETEC vaccine candidates and therapeutics.

Leptospirosis is a neglected zoonotic disease with worldwide endemicity and continues to be a significant public health burden on resource-limited populations. Previously, we produced three highly purified recombinant antigens (rLipL32, rLipL41, and rLigA-Rep) and evaluated their performance of detecting Leptospira-specific antibodies in enzyme-linked immunosorbent assay (ELISA) as compared with the microscopic agglutination test (MAT). The overall sensitivity of this assay approached 90%. Recently, another recombinant antigen (rLigB-Rep) was prepared. We tested each individual antigen and a 1:1:1:1 mixture of these four antigens for the detection of Leptospira-specific antibodies in ELISA. The performance of these recombinant antigens was evaluated with a much larger febrile patient panel (337 MAT-confirmed positive sera and 92 MAT-negative sera from febrile patients). Combining the detection results of immunoglobulin M and immunoglobulin G from these four individual antigens, the overall sensitivity was close to 90% but the specificity was only 66%, based on the MAT reference method. The overall sensitivity and specificity of the four-antigen mixture were 82% and 86%, respectively. The mixture of four antigens also exhibited a broader reactivity with MAT-positive samples of 18 serovars from six major pathogenic Leptospira species. Given the limitations of MAT, the data were further analyzed by Bayesian latent class model, showing that ELISA using a 1:1:1:1 mixture still maintained high sensitivity (79%) and specificity (88%) as compared with the sensitivity (90%) and specificity (83%) of MAT. Therefore, ELISA using a mixture of these four antigens could be a very useful test for seroprevalence studies.

Multidrug-resistant bacterial pathogens are an increasing threat to public health, and lytic bacteriophages have reemerged as a potential therapeutic option. In this work, we isolated and assembled a five-member cocktail of wild phages against Acinetobacter baumannii and demonstrated therapeutic efficacy in a mouse full-thickness dorsal infected wound model. The cocktail lowers the bioburden in the wound, prevents the spread of infection and necrosis to surrounding tissue, and decreases infection-associated morbidity. Interestingly, this effective cocktail is composed of four phages that do not kill the parent strain of the infection and one phage that simply delays bacterial growth in vitro via a strong but incomplete selection event. The cocktail here appears to function in a combinatorial manner, as one constituent phage targets capsulated A. baumannii bacteria and selects for loss of receptor, shifting the population to an uncapsulated state that is then sensitized to the remaining four phages in the cocktail. Additionally, capsule is a known virulence factor for A. baumannii , and we demonstrated that the emergent uncapsulated bacteria are avirulent in a Galleria mellonella model. These results highlight the importance of anticipating population changes during phage therapy and designing intelligent cocktails to control emergent strains, as well as the benefits of using phages that target virulence factors. Because of the efficacy of this cocktail isolated from a limited environmental pool, we have established a pipeline for developing new phage therapeutics against additional clinically relevant multidrug-resistant pathogens by using environmental phages sourced from around the globe.

Enterotoxigenic Escherichia coli (ETEC) are the most common cause of bacterial diarrhea in young children in developing countries and in travelers. Efforts to develop an ETEC vaccine have intensified in the past decade, and intestinal colonization factors (CFs) are somatic components of most investigational vaccines. CFA/I and related Class 5 fimbrial CFs feature a major stalk-forming subunit and a minor, antigenically conserved tip adhesin. We hypothesized that the tip adhesin is critical for stimulating antibodies that specifically inhibit ETEC attachment to the small intestine. To address this, we compared the capacity of donor strand complemented CfaE (dscCfaE), a stabilized form of the CFA/I fimbrial tip adhesin, and CFA/I fimbriae to elicit anti-adhesive antibodies in mice, using hemagglutination inhibition (HAI) as proxy for neutralization of intestinal adhesion. When given with genetically attenuated heat-labile enterotoxin LTR192G as adjuvant by intranasal (IN) or orogastric (OG) vaccination, dscCfaE exceeded CFA/I fimbriae in eliciting serum HAI titers and anti-CfaE antibody titers. Based on these findings, we vaccinated Aotus nancymaae nonhuman primates (NHP) with dscCfaE alone or admixed with one of two adjuvants, LTR192G and cholera toxin B-subunit, by IN and OG administration. Only IN vaccination with dscCfaE with either adjuvant elicited substantial serum HAI titers and IgA and IgG anti-adhesin responses, with the latter detectable a year after vaccination. In conclusion, we have shown that dscCfaE elicits robust HAI and anti-adhesin antibody responses in both mice and NHPs when given with adjuvant by IN vaccination, encouraging further evaluation of an ETEC adhesin-based vaccine approach.

Thyroid hormones (THs) regulate vertebrate growth, development, and metabolism. Despite their importance, there is a need for effective detection of TH-disruption by endocrine disrupting chemicals (EDCs). The frog olfactory system substantially remodels during TH-dependent metamorphosis and the objective of the present study is to examine olfactory system gene expression for TH biomarkers that can evaluate the biological effects of complex mixtures such as municipal wastewater. We first examine classic TH-response gene transcripts using reverse transcription-quantitative real-time polymerase chain reaction (RT-qPCR) in the olfactory epithelium (OE) and olfactory bulb (OB) of premetamorphic Rana (Lithobates) catesbeiana tadpoles after 48 h exposure to biologically-relevant concentrations of the THs, 3,5,3′-triiodothyronine (T3) and L-thyroxine (T4), or 17-beta estradiol (E2); a hormone that can crosstalk with THs. As the OE was particularly sensitive to THs, further RNA-seq analysis found >30,000 TH-responsive contigs. In contrast, E2 affected 267 contigs of which only 57 overlapped with THs suggesting that E2 has limited effect on the OE at this developmental phase. Gene ontology enrichment analyses identified sensory perception and nucleoside diphosphate phosphorylation as the top affected terms for THs and E2, respectively. Using classic and additional RNA-seq-derived TH-response gene transcripts, we queried TH-disrupting activity in municipal wastewater effluent from two different treatment systems: anaerobic membrane bioreactor (AnMBR) and membrane enhanced biological phosphorous removal (MEBPR). While we observed physical EDC removal in both systems, some TH disruption activity was retained in the effluents. This work lays an important foundation for linking TH-dependent gene expression with olfactory system function in amphibians.

Skin and soft tissue infections (SSTIs) are a common occurrence in health care facilities with a heightened risk for immunocompromised patients. Klebsiella pneumoniae has been increasingly implicated as the bacterial agent responsible for SSTIs, and treatment can be challenging as more strains become multidrug resistant (MDR). Therefore, new treatments are needed to counter this bacterial pathogen. Gallium complexes exhibit antimicrobial activity and are currently being evaluated as potential treatment for bacterial infections. In this study, we tested a topical formulation containing gallium citrate (GaCi) for the treatment of wounds infected with K. pneumoniae . First, the MIC against K. pneumoniae ranged from 0.125 to 2.0 μg/ml GaCi. After this in vitro efficacy was established, two topical formulations with GaCi (0.1% [wt/vol] and 0.3% [wt/vol]) were tested in a murine wound model of MDR K. pneumoniae infection. Gross pathology and histopathology revealed K. pneumoniae -infected wounds appeared to close faster with GaCi treatment and were accompanied by reduced inflammation compared to those of untreated controls. Similarly, quantitative indications of infection remediation, such as reduced weight loss and wound area, suggested that treatment improved outcomes compared to those of untreated controls. Bacterial burdens were measured 1 and 3 days following inoculation, and a 0.5 to 1.5 log reduction of CFU was observed. Lastly, upon scanning electron microscopy analysis, GaCi treatment appeared to prevent biofilm formation on dressings compared to those of untreated controls. These results suggest that with more preclinical testing, a topical application of GaCi may be a promising alternative treatment strategy for K. pneumoniae SSTI.

Background: Detailed information on the sexual behavior of bisexual, non–gay-identified men and the relationship between same-sex behavior and HIV/sexually transmitted infection (STI) incidence is limited. This study provides information on the sexual behavior with male partners of non–gay-identified men in urban, coastal Peru and the relationship of this behavior with HIV/STI incidence. Methods: We analyzed data from 2146 non–gay-identified men with a baseline and then 2 years of annual follow-up, including detailed information on sexual behavior with up to 5 sex partners, to determine the characteristics associated with bisexual behavior. Discrete time proportional hazards models were used to determine the effect of self-reported sex with men on subsequent HIV/STI incidence. Results: Over the 3 study visits, sex with a man was reported by 18.9% of men, 90% of whom also reported sex with a female partner. At baseline, reported bisexual behavior was associated with other sexual risk behaviors such as exchanging sex for money and increased risk of HIV, herpes simplex virus type 2, and gonorrhea. The number of study visits in which recent sex with men was reported was positively correlated with risk of other sexual risk behaviors and incident HIV, herpes simplex virus type 2, and gonorrhea. Recent sex with a man was associated with increased HIV/STI incidence (hazard ratio, 1.79; confidence interval, 1.19–2.70), after adjusting for sociodemographics and other sexual risk behaviors. Conclusions: Given the prevalence of recent sex with men and the relationship of this behavior with HIV/STI incidence, interventions with non–gay-identified men who have sex with men and their partners are warranted.

While it is evident that nasal colonization with S. aureus increases the likelihood of SSTI, there is a significant lack of information regarding the contribution of extranasal colonization to the overall risk of a subsequent SSTI. Furthermore, the impact of S. aureus colonization on bacterial community composition outside the nasal microbiota is unclear. Thus, this report represents the first investigation that utilized both culture and high-throughput sequencing techniques to analyze microbial dysbiosis at multiple body sites of healthy and diseased/colonized individuals. The results described here may be useful in the design of future methodologies to treat and prevent SSTIs., Skin and soft tissue infections (SSTIs) are common in the general population, with increased prevalence among military trainees. Previous research has revealed numerous nasal microbial signatures that correlate with SSTI development and Staphylococcus aureus colonization. Thus, we hypothesized that the ecology of the inguinal, oropharynx, and perianal regions may also be altered in response to SSTI and/or S. aureus colonization. We collected body site samples from 46 military trainees with purulent abscess (SSTI group) as well as from 66 asymptomatic controls (non-SSTI group). We also collected abscess cavity samples to assess the microbial composition of these infections. Samples were analyzed by culture, and the microbial communities were characterized by high-throughput sequencing. We found that the nasal, inguinal, and perianal regions were similar in microbial composition and significantly differed from the oropharynx. We also observed differences in Anaerococcus and Streptococcus abundance between the SSTI and non-SSTI groups for the nasal and oropharyngeal regions, respectively. Furthermore, we detected community membership differences between the SSTI and non-SSTI groups for the nasal and inguinal sites. Compared to that of the other regions, the microbial compositions of the nares of S. aureus carriers and noncarriers were dramatically different; we noted an inverse correlation between the presence of Corynebacterium and the presence of Staphylococcus in the nares. This correlation was also observed for the inguinal region. Culture analysis revealed elevated methicillin-resistant S. aureus (MRSA) colonization levels for the SSTI group in the nasal and inguinal body sites. Together, these data suggest significant microbial variability in patients with SSTI as well as between S. aureus carriers and noncarriers. IMPORTANCE While it is evident that nasal colonization with S. aureus increases the likelihood of SSTI, there is a significant lack of information regarding the contribution of extranasal colonization to the overall risk of a subsequent SSTI. Furthermore, the impact of S. aureus colonization on bacterial community composition outside the nasal microbiota is unclear. Thus, this report represents the first investigation that utilized both culture and high-throughput sequencing techniques to analyze microbial dysbiosis at multiple body sites of healthy and diseased/colonized individuals. The results described here may be useful in the design of future methodologies to treat and prevent SSTIs.

Military trainees are at high risk for skin and soft-tissue infections (SSTIs). Although Staphylococcus aureus is associated with purulent SSTI, it is unclear to what degree this pathogen causes nonpurulent cellulitis. To inform effective prevention strategies and to provide novel insights into SSTI pathogenesis, we aimed to determine the etiology of SSTI in this population. We conducted a prospective observational study in US Army Infantry trainees with SSTI (cutaneous abscesses and cellulitis) from July 2012 through December 2014. We used standard microbiology, serology, and high-throughput sequencing to determine the etiology of SSTI. Furthermore, we compared purported risk factors as well as anatomic site colonization for S. aureus. Among 201 SSTI cases evaluated for SSTI risk factors, cellulitis was associated with lower extremity blisters (P = 0.01) and abscess was associated with methicillin-resistant S. aureus (MRSA) colonization (P

Role-based sexual identities structure male same-sex partnerships and influence HIV/STI epidemiology among MSM in Latin America. We explored shifting relationships between sexual roles, identities and practices among MSM in Lima, Peru, and implications for HIV/STI prevention. Patterns of HIV/STI epidemiology reflected differential risks for transmission within role-based partnerships with relatively low prevalences of HIV, syphilis, and HSV-2 but higher prevalences of urethral gonorrhea/chlamydia among activo MSM compared with moderno and pasivo participants. Qualitative analysis of how MSM in Peru integrate sexual identities, roles, and practices identified four key themes: pasivo role as a gay approximation of cultural femininity; activo role as a heterosexual consolidation of masculinity; moderno role as a masculine reconceptualization of gay identity; and role-based identities as social determinants of partnership, network, and community formation. The concept of role-based sexual identities provides a framework for HIV prevention for Latin American MSM that integrates sexual identities, practices, partnerships, and networks. Las identidades basadas en roles sexuales forman la estructura de las relaciones de pareja e influyen en la epidemiología del VIH/ITS entre HSH en América Latina. Se exploró la relación cambiante entre roles, identidades, y practicas sexuales en HSH en Lima, Perú y las implicaciones para la prevención del VIH. Los patrones epidemiológicos del VIH/ITS mostraron diferencias en riesgos de transmisión en parejas definidas por roles sexuales con una prevalencia relativamente baja de VIH, sífilis, y HSV-2, pero una prevalencia alta de gonorrea/clamidia uretral en HSH activos en comparación a modernos y pasivos. El análisis cualitativo de como los HSH en el Perú integran sus identidades, roles y practicas identificó cuatro ejes temáticos: El rol pasivo como una aproximación gay de la feminidad cultural; el rol activo como una consolidación heterosexual de la masculinidad; el rol moderno como una reconceptualización masculina de la identidad gay; y las identidades basadas en roles sexuales como determinantes de la formación de parejas, redes, y comunidades. El concepto de identidades sexuales basadas en roles sexuales ofrece un marco analítico para la prevención del VIH entre HSH Latinoamericanos que puede integrar las identidades, prácticas, parejas, y redes sexuales.

Analysis of plant sterols in pulp mill effluents is complex and several investigations have combined wood extractives with sterols or have reported total sterols collectively. The present study exclusively focuses on the fate of individual sterols generated in pulp and paper manufacturing as they pass through activated sludge biotreatment system. Before secondary treatment the pulp mill effluents contained 33% ß-sitosterol, 26% campesterol, 22% ß-sitostanol, 17% stigmasterol and 2% ergosterol (1,000–1,800 μg/L mean total sterols). After treatment, the effluents contained 44% ß-sitosterol, 22% campesterol, 18% ß-sitostanol, 14% stigmasterol and 2% ergosterol (176–428 μg/L mean total sterols). Each sterol fraction showed different removal efficiency. ß-Sitosterol, the major fraction, was removed relatively poorly (65%) while campesterol was removed most efficiently (81%) compared with the removal of other fractions (ß-sitostanol 74% and stigmasterol 64%). The differential removal of sterol fractions altered the sterol profile during different stages of the secondary treatment. Owing to its poor removal, ß-sitosterol is the most persistent fraction in treated/untreated pulp mill effluents. Typically, 21% of the incoming sterols were contained in secondary effluents and 23% in waste sludge without biodegradation. Optimizing the design/operation of treatment systems for removal of ß-sitosterol and stigmasterol would improve the performance of effluent treatment facilities.

We analyzed a randomly selected group of 30 diffusely adherent (DAEC), 30 enteropathogenic, 30 enteroaggregative, and five Shiga toxin-producing Escherichia coli strains isolated from children with diarrhea. Enterotoxigenic E. coli (ETEC) colonization factors (CFs) were evaluated by a dot-blot assay using 21 CF-specific monoclonal antibodies. Out of 95 non-ETEC strains, three DAEC were found to express coli surface antigen 20 (CS20). No other E. coli expressed CFs. We confirmed the three CS20-positive strains as ETEC-negative by repeat PCR and as toxin-negative by ganglioside-GM1-enzyme-linked immunosorbent assay. To our knowledge, this is the first study that has identified currently recognized CFs in non-ETEC diarrheagenic E. coli strains identified using molecular methods. CFs may be an unrecognized relevant adherence factor in other E. coli, which may then play a role in pathogenesis and the immune response of the host.

Enterotoxigenic Escherichia coli (ETEC) is a major cause of childhood diarrhea. The present study sought to determine the prevalence and distribution of toxin types, colonization factors (CFs), and antimicrobial susceptibility of ETEC strains isolated from Peruvian children. We analyzed ETEC strains isolated from Peruvian children between 2 and 24 months of age in a passive surveillance study. Five E. coli colonies per patient were studied by multiplex real-time PCR to identify ETEC virulence factors. ETEC-associated toxins were confirmed using a GM1-based enzyme-linked immunosorbent assay. Confirmed strains were tested for CFs by dot blot assay using 21 monoclonal antibodies. We analyzed 1,129 samples from children with diarrhea and 744 control children and found ETEC in 5.3% and 4.3%, respectively. ETEC was more frequently isolated from children >12 months of age than from children P < 0.001). Fifty-two percent of ETEC isolates from children with diarrhea and 72% of isolates from controls were heat-labile enterotoxin (LT) positive and heat-stable enterotoxin (ST) negative; 25% and 19%, respectively, were LT negative and ST positive; and 23% and 9%, respectively, were LT positive and ST positive. CFs were identified in 64% of diarrheal samples and 37% of control samples ( P < 0.05). The most common CFs were CS6 (14% and 7%, respectively), CS12 (12% and 4%, respectively), and CS1 (9% and 4%, respectively). ST-producing ETEC strains caused more severe diarrhea than non-ST-producing ETEC strains. The strains were most frequently resistant to ampicillin (71%) and co-trimoxazole (61%). ETEC was thus found to be more prevalent in older infants. LT was the most common toxin type; 64% of strains had an identified CF. These data are relevant in estimating the burden of disease due to ETEC and the potential coverage of children in Peru by investigational vaccines.

Biosorption has potential to be an economical colour removal technology. As such, the colour removal potential of inactivated Aspergillus niger biomass was investigated for the treatment of activated sludge-treated pulp mill effluent from a northern bleached softwood kraft mill. Biomass pretreatment methods, effects of initial pH of the effluent and preparative biomass washing methods were examined. The most effective pretreatment method was found to be simple autoclaving of the biomass and this approach was applied in subsequent kinetic and isotherm batch studies. It was also found that the pH of the wastewater prior to addition of the biomass affected the biosorption rate and the solubility of chromophores in pulp mill effluent. The results also indicated that biomass washing methods reduced the quantity of organic matter leached from the fungal biomass during application. The kinetic study revealed that colour removal by biosorption occurred most readily in the first 8 h and could be described adequately by both the Lagergren and Ho et al. models. The maximum colour removal was over 900 TCU, with a biomass dose of about 20 g/L. The isotherm study data were fitted with the BET isotherm model. The results indicated that adsorption occurred in a multi-layer fashion and that physical adsorption was the main mechanism contributing to the biosorption. Therefore, dead A. niger biomass was concluded to be a promising alternative for colour removal from pulp mill effluent.

Background. Enteropathogenic Escherichia coli (EPEC) strains are pediatric pathogens commonly isolated from both healthy and sick children with diarrhea in areas of endemicity. The aim of this study was to compare the bacterial load of EPEC isolated from stool samples from children with and without diarrhea to determine whether bacterial load might be a useful tool for further study of this phenomenon. Methods. EPEC was detected by polymerase chain reaction (PCR) of colonies isolated on MacConkey plates from 53diarrheal and 90healthychildrenaged,2 years. DNA was isolatedfromstool samplesby cetyltrimethylammonium bromide extraction. To standardize quantification by quantitative real-time PCR (qRT-PCR), the correlation between fluorescence threshold cycle and copy number of the intimin gene of EPEC E2348/69 was determined. Results. The detection limit of qRT-PCR was 5 bacteria/mg stool. The geometric mean load in diarrhea was 299 bacteria/mg (95% confidence interval [CI], 77‐1164 bacteria/mg), compared with 29 bacteria/mg (95% CI, 10‐87 bacteria/mg) in control subjects (P 5 .016). Bacterial load was significantly higher in children with diarrhea than in control subjects among children ,12 months of age (178 vs 5 bacteria/mg; P 5 .006) and among children with EPEC as the sole pathogen (463 vs 24 bacteria/mg; P 5 .006). Conclusions. EPEC load measured by qRT-PCR is higher in diarrheal than in healthy children. qRT-PCR may be useful to study the relationship between disease and colonization in settings of endemicity.

As mathematical modeling of wastewater treatment plants has become more common in research and consultancy, a mismatch between education and requirements for model-related jobs has developed. There seems to be a shortage of skilled people, both in terms of quantity and in quality. In order to address this problem, this paper provides a framework to outline different types of model-related jobs, assess the required skills for these jobs and characterize different types of education that modelers obtain “in school” as well as “on the job”. It is important to consider that education of modelers does not mainly happen in university courses and that the variety of model related jobs goes far beyond use for process design by consulting companies. To resolve the mismatch, the current connection between requirements for different jobs and the various types of education has to be assessed for different geographical regions and professional environments. This allows the evaluation and improvement of important educational paths, considering quality assurance and future developments. Moreover, conclusions from a workshop involving practitioners and academics from North America and Europe are presented. The participants stressed the importance of non-technical skills and recommended strengthening the role of realistic modeling experience in university training. However, this paper suggests that all providers of modeling education and support, not only universities, but also software suppliers, professional associations and companies performing modeling tasks are called to assess and strengthen their role in training and support of professional modelers.

The multiple-locus variable-number repeat analysis of 90 human Brucella melitensis isolates from a large urban area in central Peru revealed variations at 4 (Bruce07, Bruce09, Bruce18, and Bruce42) out of 16 loci investigated, of which 1 (Bruce42) also is used for species identification. Ten genotypes were identified, separated by the number of Bruce42 repeats into two groups that may have distinct phenotypic characteristics. Whereas genotypes with five or six Bruce42 repeats were cultured mainly from adult patients, genotypes with three Bruce42 repeats were isolated from children and young adolescents as well as from adults. In addition, the isolates with three Bruce42 repeats were obtained more often from patients with splenomegaly ( P = 0.02) or hepatomegaly ( P = 0.006). An annual variation in the diversity of genotypes was observed, possibly reflecting changes in sources of fresh dairy products, supply routes to city shops and markets, and the movement of infected dairy goat herds.

A collection of environmental and clinical strains of Vibrio cholerae O1 isolated from the beginning of the Latin American epidemic of cholera in 1991 to 2003 from multiple locations in Peru were characterized and compared with V. cholerae O1 El Tor strains of the seventh pandemic from the rest of the world (Asia, Africa, Australia and Europe) using a multilocus virulence gene profiling strategy and DNA sequencing. Peruvian strains differed from El Tor strains from the rest of the world by the failure of PCR to amplify genes VC0512, VC0513, VC0514 and VC0515 in the Vibrio seventh pandemic island-II (VSP-II) gene cluster. Sequencing of the VSP-II gene cluster and its flanking regions in one Peruvian strain (PERU-130) confirmed the PCR results, indicating that the Peruvian strain had low DNA homology (46.6 %) compared to the reference strain N16961 within the VSP-II region encompassing genes VC0511 to VC0515. Based on these differences in VSP-II, and based on the overall similarity between the pulsotypes of the Peruvian strains and the El Tor reference strain N16961, we concluded that the Peruvian, Eurasian and African strains belonged to the same clonal complex, and that the Peruvian strains represented variants that had independently evolved for a relatively short time. Since these ORFs in VSP-II of Peruvian strains are unique and conserved, they could form the basis for tracking the origin of the Peruvian strains and therefore of the Latin American pandemic.

The roles of various mixed liquor constituents in the membrane filtration of activated sludge were investigated. Bench-scale filtration tests with four mixed liquor fractions (whole mixed liquor, mixed liquor supernatant, filtrate I ( 8.0 μm). In particular, the study revealed that large flocs were able to exert dual effects on membrane filtration. Depending on the hydrodynamic conditions, they could either act as membrane foulants causing fouling via particle deposition and cake formation,...

Objectives: To assess the prevalence of sexually transmitted infections (STIs), the frequency of sexual risk behaviours, and the relation between knowledge of HIV infection status and sexual risk behaviour among men who have sex with men (MSM) infected with HIV attending an STI clinic in Peru. Methods: We recruited a convenience sample of 559 MSM from a municipal STI clinic in Lima, Peru. Participants completed a survey and provided blood for HIV, syphilis and HSV-2 antibody testing, and urine for gonorrhoea and chlamydia nucleic acid testing. Results: Among 124 MSM with HIV, 72.6% were aware that they were infected with HIV. Active syphilis (RPR>1:8) was diagnosed in 21.0% of men infected with HIV, HSV-2 in 79.8%, urethral gonorrhoea in 1.6% and chlamydia in 1.6%. Among 41 participants reporting insertive anal intercourse with their last sex partner, 34.2% did not use a condom. Of the 86 participants reporting receptive anal intercourse, 25.6% did not use a condom. At least one episode of insertive unprotected anal intercourse (UAI) with a partner uninfected with HIV during the past 6 months was reported by 33.6% (35/ 104) of participants, and receptive UAI with a partner uninfected by HIV was reported by 44.6% (45/101). There was no difference in frequency of UAI with partners infected or uninfected with HIV observed between men who knew their serostatus compared with those who were previously undiagnosed (all p values .0.05). Conclusions: MSM with HIV in Peru engaged in high-risk behaviours for spreading HIV and STIs. Knowledge of whether someone was infected with HIV was not associated with a decreased frequency of UAI. Additional efforts to reduce risk behaviour after the diagnosis of HIV infection are necessary.

OBJECTIVE. Our goal was to estimate the impact of a Shigella vaccine in an area where shigellosis is endemic by characterizing the disease burden and antibiotic-resistance profiles of isolates and by determining the prevalence of Shigella flexneri serotypes. PATIENTS AND METHODS. We conducted a 43-month-long prospective, community-based diarrheal disease surveillance in 442 children RESULTS. The incidence of diarrheal disease was 4.38 episodes per child-year. The incidence rate for shigellosis was 0.34 episodes per child-year in children CONCLUSIONS. Children living in this region had a 20-fold higher rate of disease incidence detected by active surveillance as those recently estimated by passive detection. Most symptomatic disease was caused by S flexneri, although the diversity of serotypes will require a multivalent vaccine to have a significant impact on the burden of disease caused by shigellosis. Several other public health disease-control interventions targeted at water source and improved storage, nutritional interventions, and improved maternal education seem to have a greater impact than a univalent S flexneri 2a vaccine.

An oral, microencapsulated anti-colonization factor 6 antigen (meCS6) vaccine, with or without heat-labile enterotoxin with mutation R192G (LT R192G ) (mucosal adjuvant), against enterotoxigenic Escherichia coli (ETEC) was evaluated for regimen and adjuvant effects on safety and immunogenicity. Sixty subjects were enrolled into a three-dose, 2-week interval or four-dose, 2-day interval regimen. Each regimen was randomized into two equal groups of meCS6 alone (1 mg) or meCS6 with adjuvant (2 μg of LT R192G ). The vaccine was well tolerated and no serious adverse events were reported. Serologic response to CS6 was low in all regimens (0 to 27%). CS6-immunogloublin A (IgA) antibody-secreting cell (ASC) responses ranged from 36 to 86%, with the highest level in the three-dose adjuvanted regimen; however, the magnitude was low. As expected, serologic and ASC LT responses were limited to adjuvanted regimens, with the exception of fecal IgA, which appeared to be nonspecific to LT administration. Further modifications to the delivery strategy and CS6 and adjuvant dose optimization will be needed before conducting further clinical trials with this epidemiologically important class of ETEC.

Pulp and paper mill effluents (PPMEs) may contain high levels of otherwise naturally occurring organic pollutants such as plant sterols, which are suspected endocrine disrupting chemicals. Exposure to such chemicals may cause various physiological and morphological abnormalities that have been reported in the fish and other aquatic life inhabiting PPME receiving waters. Plant sterols, or phytosterols, form a constituent of wood extractives that may be released into the effluents during the pulping and paper making processes. Isolation and analysis of sterols from the complex mixture of PPMEs is challenging and standard analytical protocols do not exist. The need for having a reliable method for analyzing a particular environmental contaminant such as plant sterols cannot be overemphasized. In the present study a technique was modified for reliable analysis of PPME sterols. The technique involves liquid-liquid extractions using methyl-t-butyl ether and trimethyl-silylation derivatizations of the extracted sterols. Identification and quantification of the PPME sterols were accomplished by gas chromatography and mass spectrometry. Analytical problems were resolved by conducting multiple extractions, drying the sterol extracts, and redissolving and silylating the extracts at an increased derivatization temperature of 70°C. This shortened the suggested incubation period from 12 to 4 h. The modified technique offered improved method sensitivity and reproducibility, and successfully quantified campesterol, β-sitosterol, β-sitostanol, stigmasterol, stigmastanol, cholesterol, and ergosterol in PPMEs. Primary and secondary treated PPMEs analyses suggested 800 ± 190 µg/L total sterols in primary effluents, and 211 ± 90 µg/L in biologically treated final effluents. β-Sitosterol, β-sitostanol, and campesterol alone accounted for about 80% of the total sterols. A general comparison of the sterols in primary and secondary effluents suggested about 73% removal across the secondary treatment systems sampled.

During home visits and using a point-of-care test for brucellosis, we screened the household members of adult patients found to have brucellosis by investigation at the Hospital Nacional Daniel Alcides Carrion in Callao, Peru. A total of 206 household members of 43 patients were screened, and 15 (7.3%) household members in 10 (23.3%) households tested seropositive. Brucellosis was diagnosed in 14 of them, all but 4 presenting with acute or subacute uncomplicated disease. Regardless of attempts to control brucellosis in Peru, the disease continues to be reasonably common among household members of brucellosis patients. Household members presumably remain the single most important identifiable risk group in an urban setting, and screening them provides an effective means for their early diagnosis. Although contact with livestock was rare, the consumption of unpasteurized dairy products was reported by almost all patients with brucellosis, their household members, and hospitalized non-brucellosis patients.

The physical and biochemical properties of activated sludge mixed liquor, including floc size distribution, zeta potential, relative hydrophobicity, and bound and unbound (soluble) extracellular polymeric substances (EPS), were examined in this study to evaluate their relationship to membrane fouling. Mixed liquors from a membrane enhanced biological phosphorus removal (MEBPR) process and a conventional enhanced biological phosphorus removal (CEBPR) process were compared. It was found that the floc size distribution and the amount of soluble EPS in the mixed liquor were the most important properties that significantly influenced the fouling propensity of sludge. Contrary to the literature, the content of EPS bound in activated sludge flocs was not found to be directly associated with membrane fouling, and sludge surface properties such as zeta potential and relative hydrophobicity were not closely related to the observed differences in the fouling tendencies of the two types of sludge.

A long-term comparative study on the kinetics of enhanced biological phosphorus removal (EBPR) was carried out in pilot scale membrane-assisted and conventional biological phosphorus removal processes, by monitoring system performance, phosphorus mass balances, and maximum specific rates in off-line batch tests. The two systems exhibited similar performance in the removal of soluble phosphorus (P) from the influent wastewater, in the specific P release observed in the anaerobic zone, and in the maximum specific P release and volatile fatty acid (VFA) uptake rates. However, when the VFA in the influent was limiting, the conventional EBPR (CEBPR) process performed significantly better than the membrane (MEBPR) counterpart, and this behavior was also reflected in the kinetics of P release. Denitrifying dephosphatation was observed to be significant in both processes during periods of satisfactory P removal. When the aerobic recycle ratio was reduced to a minimum level, the anoxic P uptake activity in the CEBPR sludge was lower than that of the MEBPR sludge. Finally, the biomass decay rates of the two sludge types were estimated to be comparable, with significant reduction of the decay under unaerated conditions.

Gas sparging is a common strategy used to minimize and prevent fouling on membrane surfaces. Although there have been numerous studies on the hydrodynamic conditions and the mechanisms of fouling control in confined membrane systems such as tubular membranes, there is very limited literature available that describes the hydrodynamic conditions and mechanisms of fouling control in unconfined systems such as submerged hollow fiber membranes. The present study investigated bubble-induced shear profiles in submerged hollow fiber membrane modules using an electrochemical method for measuring shear forces. The effects of different operating conditions such as gas sparging rates, fiber packing densities, diffuser nozzle sizes, and module configurations (i.e. loosely versus tightly held) on shear profiles were studied. It was found that the hydrodynamic conditions in confined tubular membrane systems and unconfined submerged hollow fiber membranes are different, which implies that the mechanisms of fouling control in submerged hollow fiber membrane units may be different than those in confined systems such as the tubular membranes. Surface shear profiles during sparging were found to be substantially affected by the operating conditions (i.e. gas sparging rate, fiber packing density, diffuser nozzle size, and module configuration). The different shear profiles were due to the different bubble geometries and flow paths which resulted from the different operating conditions considered. For tightly held low and medium fiber packing density bundles the high number of shear events generated by small bubbles (i.e. small diffuser nozzle) resulted in more favorable hydrodynamic condition for fouling reduction and flux enhancement. The higher permeate fluxes that have been reported in loosely held submerged hollow fiber membrane systems likely result from the larger number of fibers (i.e. regions) that can be impacted by sparged bubbles in systems with loosely held fibers. The results from the present study provide a better understanding of the hydrodynamic conditions inside submerged hollow fiber membrane modules, and therefore a better understanding of possible mechanisms of fouling control via gas sparging.

The mechanisms of membrane fouling in a pilot scale membrane enhanced biological phosphorus removal (MEBPR) system were investigated. It was found that the long-term fouling in the MEBPR process was hydraulically irreversible and was attributed to organic adsorption and deep pore clogging. The reversible fouling caused by sludge deposition and/or superficial pore blocking was reduced to the minimum due to the vigorous aeration and frequent backflushing applied. Soluble organic substances, such as soluble microbial products (SMP), were thought to be responsible for the irreversible fouling. The mixed liquor with higher SMP concentrations exhibited a greater fouling propensity than the mixed liquor with lower SMP concentrations. The significance of soluble organic substances to the irreversible fouling was confirmed through modeling of the evolution of trans-membrane pressure (TMP) in the MEBPR process. The modeling results indicated that the long-term irreversible fouling in the MEBPR process followed a simple exponential relationship with filtration time, volume of permeate filtered, or cumulative loading of soluble COD on the membranes. In particular, the degree of the irreversible fouling observed was most closely related to the cumulative amount of soluble organic material carried to the membranes by the flux of mixed liquor during the filtration process. Operating flux and/or process hydraulic retention time had little impact on the evolution of the organic loading-based irreversible fouling.

Enterotoxigenic Escherichia coli (ETEC)-induced diarrhea is recognized frequently in individuals who travel in developing countries around the world (4, 7, 8, 26, 29, 47) and is a major medical problem for military personnel deployed in these countries (26, 44, 45). Since strict personal hygiene and avoidance of local water and fresh and undercooked foods are recommendations with which travelers have difficulty complying, other means to reduce the ETEC attack rate must be considered. The use of short-term chemoprophylaxis and self-treatment for diarrhea are effective for travelers who are unwilling to accept even a short period of illness because of the serious impact it would have on their overall mission. However, the routine use of antimicrobial prophylaxis for the general traveler is not recommended because of the potential for associated adverse drug reactions and the potential to worsen the problem of antibiotic resistance of enteric bacteria (8, 25, 29, 43, 47). These factors make development of vaccines against ETEC a priority. ETEC strains produce a heat-labile toxin (LT) and/or a heat-stable toxin (ST) that are largely responsible for the symptoms of diarrhea. LT is immunogenic, but ST is a peptide and nonimmunogenic. ETEC strains also express antigenically distinct fimbriae collectively termed colonization factors (CF) (5). The most common CF include colonization factor antigen I (CFA/I), CFA/II, and CS6 (59). The protective role of the host immune response to specific antigens, such as CF or toxins, or of specific components of the immune system, such as secretory immunoglobulin A (IgA) in the intestine, is not well defined. Previous studies showed that CF were protective when volunteers were challenged with homologous strains of ETEC after they were either passively immunized with immunoglobulin with specific activity against CF (18, 54) or actively immunized or infected (9, 12, 14, 34, 36, 37, 55). Antitoxic protection based on an immune response to the heat-labile toxin was suggested based on field trials by Clemens et al. (6), who used the B subunit of whole-cell cholera vaccine and induced cross-protection against severe diarrhea caused by ETEC LT in immunized volunteers. The data described above suggest that an ETEC vaccine would have to include the most prevalent colonization factors and have antitoxin activity. Thus, vaccine development is complicated because a vaccine would require several CF, as well as LT, and would require tests of a number of vaccine prototypes. Because there is no established immunological correlate of protection against ETEC diarrhea, the efficacy of vaccine candidates that are developed is likely to be evaluated after a direct challenge to humans with ETEC. The use of human volunteers for studying immunity and the pathogenesis of ETEC infection after oral ingestion of strain B7A or {"type":"entrez-nucleotide","attrs":{"text":"H10407","term_id":"875229","term_text":"H10407"}}H10407 has been described previously. ETEC strain B7A has been given to nearly 50 volunteers (9, 35, 36). B7A is a serotype O148:H28 strain and expresses LT, ST, CS6 (40), longus (19), and an unidentified adhesin (33). The most common symptoms in volunteers challenged with B7A were diarrhea, abdominal cramps, and malaise. Previous exposure to B7A protected volunteers from illness but not shedding (36). The level of serum antibody response to lipopolysaccharide varied from 20 to 90% (9, 36), but the immune response to other antigens has not been reported. E. coli strain {"type":"entrez-nucleotide","attrs":{"text":"H10407","term_id":"875229","term_text":"H10407"}}H10407 is the most commonly used ETEC challenge strain and has been given to over 200 volunteers (2, 11-14, 18, 20, 35, 37, 54). It is a serotype O78:K80:H11 strain and was isolated from an adult with severe diarrhea in Dacca, Bangladesh (13). {"type":"entrez-nucleotide","attrs":{"text":"H10407","term_id":"875229","term_text":"H10407"}}H10407 expresses the enterotoxins LT (50), ST (both STIa and STIb) (41), and CFA/I (13). It also expresses EAST (60), Tia (15), Tib (38), Leo (16), and EatA (46), which may play roles in virulence. The symptoms in volunteers challenged with {"type":"entrez-nucleotide","attrs":{"text":"H10407","term_id":"875229","term_text":"H10407"}}H10407 were (from most frequent to least frequent) gurgling, abdominal cramps, diarrhea, anorexia, malaise, nausea or vomiting, headache, and fever. The diarrheal stool volumes ranged from 0.1 to 11 liters, and the time until onset of symptoms after challenge was typically 2 days. Nearly all challenged volunteers shed {"type":"entrez-nucleotide","attrs":{"text":"H10407","term_id":"875229","term_text":"H10407"}}H10407, and shedding lasted approximately 1 week unless the volunteers were treated with antibiotics. Previous exposure to {"type":"entrez-nucleotide","attrs":{"text":"H10407","term_id":"875229","term_text":"H10407"}}H10407 protected volunteers from illness but not shedding (37). Serum IgG responses to CFA/I, LT, and O78 were detected after challenge (13, 20, 35, 37, 49, 54) in many volunteers, but secretory IgA was assayed in only one study (35). Here we describe the first direct comparison of two well-established ETEC challenge models, B7A-induced clinical illness and {"type":"entrez-nucleotide","attrs":{"text":"H10407","term_id":"875229","term_text":"H10407"}}H10407-induced clinical illness. Clinical presentation, the effect of ciprofloxacin, and the immune responses to CS6, CFA/I, and LT are described below. The mucosal immune response was measured using antibody-secreting cells (ASC), and the systemic response from sera was measured using quantitative methods. This is the first time that the immune response to CS6 has been measured quantitatively after infection with wild-type ETEC.

Proper control of phytosterols in pulp mill effluents is necessary before disposal into receiving environments because they have been suspected to be hormonally active to aquatic life. This study provides an insight into the adsorptive behavior of sterols and the role of secondary sludge in their removal during secondary treatment. The kinetics of sterol adsorption, extent of sterol adsorption onto inactivated secondary solids, adsorptive capacity of secondary solids, and the relative contribution of the adsorption mechanism in the overall removal of sterols during secondary treatment have been investigated in this study. Isotherm modeling revealed two different adsorption regimes for each sterol. The results show that adsorption plays a major role in the secondary treatment of pulp mill effluents and that secondary sludge serves as an efficient adsorbent to remove phytosterols. The obtained information is important to improve system design and optimize the operation of pulp mill effluent treatmen...

Characterization of fouled membranes is the first step towards a good understanding of membrane fouling nature and thus formulating effective engineering measures for fouling prevention and control. In this study, fouled membrane fibres collected from a pilot scale membrane enhanced biological phosphorus removal (MEBPR) process were systematically examined. Several analytical tools, including scanning electron microscopy (SEM), conventional optical microscopy (COM), energy dispersive X-ray (EDX) microanalysis, matrix assisted laser desorption/ionization – mass spectrometry (MALDI-MS) analysis, and conventional chemical analysis techniques were used. The results indicated that membrane fouling in the MEBPR process was mainly of an organic nature, and most extractable foulants were carbohydrates and humic or humic-like substances. Unlike in other wastewater treatment membrane bioreactors, microbial growth on fouled membranes was not substantial, probably due to the vigorous aeration applied and the strong hydrodynamic conditions within the membrane pore structure. After a period of sludge filtration, membrane surfaces became more hydrophobic and the resultant hydrophobic interactions between the fouled membranes and mixed liquor constituents might have accelerated the fouling process.

Parameter estimation and wastewater characterization are crucial for modelling of the membrane enhanced biological phosphorus removal (MEBPR) process. Prior to determining the values of a subset of kinetic and stoichiometric parameters used in ASM No. 2 (ASM2), the carbon, nitrogen and phosphorus fractions of influent wastewater at the University of British Columbia (UBC) pilot plant were characterized. It was found that the UBC wastewater contained fractions of volatile acids (SA), readily fermentable biodegradable COD (SF) and slowly biodegradable COD (XS) that fell within the ASM2 default value ranges. The contents of soluble inert COD (SI) and particulate inert COD (XI) were somewhat higher than ASM2 default values. Mixed liquor samples from pilot-scale MEBPR and conventional enhanced biological phosphorus removal (CEBPR) processes operated under parallel conditions, were then analyzed experimentally to assess the impact of operation in a membrane-assisted mode on the growth yield (YH), decay coefficient (bH) and maximum specific growth rate of heterotrophic biomass (µH). The resulting values for YH, bH and µH were slightly lower for the MEBPR train than for the CEBPR train, but the differences were not statistically significant. It is suggested that MEBPR simulation using ASM2 could be accomplished satisfactorily using parameter values determined for a conventional biological phosphorus removal process, if MEBPR parameter values are not available.

A membrane-enhanced biological phosphorus removal (MEBPR) process was operated in parallel with a conventional EBPR (CEBPR) process under challenging operating conditions to uncover fundamental differences in their ability to remove chemical oxygen demand (COD), nitrogen (N), and phosphorus (P) from municipal wastewater. Both systems exhibited the same potential to achieve excellent soluble-P removal when a favorable COD to P ratio was maintained in the influent. The MEBPR train generated a superior effluent quality when measured as total P. The CEBPR effluent contained significantly lower levels of nitrates due to the extra denitrification occurring in the sludge blanket of the secondary clarifier. The observed sludge yield in the MEBPR system was estimated to be between 0.23 and 0.28 g VSS/g COD, and this was 15% lower than the CEBPR sludge yield. When the influent volatile fatty acids (VFAs) became limiting, the CEBPR train exhibited better performance in the removal of soluble-P, due to the higher observed sludge yield and an overall greater denitrification activity that led to a more efficient use of VFAs in the anaerobic zone. After experiencing a severe deterioration of the biological P activity in both processes, the MEBPR train exhibited faster recovery than the CEBPR side. In this experimental work, it was demonstrated that an MEBPR process can sustain long-term satisfactory bio-P performance at HRTs as low as 7 h. However, the lower sludge yield and the reduced denitrification capacity are two important factors that impact the design of high rate membrane-assisted biological nutrient removal (BNR) processes.

Background. We conducted a nested case-control study in 397 rural Egyptian children

Activated Sludge Model No 3 (ASM3) was chosen to model an activated sludge system treating effluents from a mechanical pulp and paper mill. The high COD concentration and the high content of readily biodegradable substrates of the wastewater make this model appropriate for this system. ASM3 was calibrated based on batch respirometric tests using fresh wastewater and sludge from the treatment plant, and on analytical measurements of COD, TSS and VSS. The model, developed for municipal wastewater, was found suitable for fitting a variety of respirometric batch tests, performed at different temperatures and food to microorganism ratios (F/M). Therefore, a set of calibrated parameters, as well as the wastewater COD fractions, was estimated for this industrial wastewater. The majority of the calibrated parameters were in the range of those found in the literature.

Resin acids are pulp mill effluent contaminants that exhibit significant solubility, diffusivity, and surfactancy changes with pH within the range typically used for biological treatment. Such physical-chemical property changes which can influence removal during biological wastewater treatment, can be characterized by dynamic surface tension measurements. Dynamic surface tension measurements were made by the maximum bubble pressure method during batch treatment of selected resin acids in pulp mill effluent. Interpretation of dynamic surface tension data was made through the framework of a quasi-static Langmuir isotherm model that was derived as part of this investigation. The results suggested that under acidic conditions, resin acids form associations with other dissolved organic matter contained in pulp mill effluent, while under alkaline conditions, they behave as relatively soluble surfactants. A resin acid residuum, or threshold concentration, has been found to increase under acidic growth conditions. This residuum increase corresponded to an inferred reduction in resin acid bioavailability that was suggested from the isotherm modelling. The development of quasi-static isotherm adsorption models has application in computer simulation for design of adsorption based unit processes, and could potentially be utilized as an informative treatment process monitor.

Transcutaneous immunization (TCI) is a new method for vaccine delivery that has been shown to induce immunity relevant to enteric disease vaccines. We evaluated the clinical safety and immunogenicity of a recombinant subunit vaccine against enterotoxigenicEscherichia coli(ETEC) delivered by TCI. Adult volunteers received patches containing the recombinant ETEC colonization factor CS6, either with heat-labile enterotoxin (LT) or patches containing CS6 alone. The vaccine was administered at 0, 1, and 3 months, and serum antibodies and antibody-secreting cells (ASCs) were assessed. Among the 26 volunteers that completed the trial, there were no responses to CS6 in the absence of LT. In the groups receiving both CS6 and LT, 68 and 53% were found to have serum anti-CS6 immunoglobulin G (IgG) and IgA, respectively; 37 and 42% had IgG and IgA anti-CS6 ASCs. All of the volunteers receiving LT had anti-LT IgG, and 90% had serum anti-LT IgA; 79 and 37% had anti-LT IgG and IgA ASCs. Delayed-type hypersensitivity (DTH), suggesting T-cell responses, was seen in 14 of 19 volunteers receiving LT and CS6; no DTH was seen in subjects receiving CS6 alone. This study demonstrated that protein antigens delivered by a simple patch could induce significant systemic immune responses but only in the presence of an adjuvant such as LT. The data suggest that an ETEC vaccine for travelers delivered by a patch may be a viable approach worthy of further evaluation.

Background. We conducted the first trial to assess the safety and immunogenicity of an oral, killed enterotoxigenic Escherichia coli plus cholera toxin B-subunit vaccine in children

This article presents an index of similarity that has application in monitoring relative changes of complex microbial communities for the purpose of understanding the impact of community instability in biological wastewater treatment systems. Gas chromatographic data quantifying microbial fatty acid esters extracted from biosolids samples can be used to infer the occurrence of changes in mixed culture community structure. One approach to rapidly assess the relative dissimilarity between samples is to calculate a similarity index scaled between 0 and 1. The many arbitrary scales that are associated with the available calculation methods for similarity indices limits the extent of application. Therefore, a specialized index of similarity was derived from consideration of the measurement errors associated with the chromatographic data. The resultant calculation method provides a clear mechanism for calibrating the sensitivity of the similarity index, such that inherent measurement variability is accommodated and standardization of scaling is achieved. The similarity index sensitivity was calibrated with respect to an effective gas chromatographic peak coefficient of variation, and this calibration was particularly important for facilitating comparisons made between different systems or experiments. The proposed index of similarity was tested with data acquired from a recently completed study of contaminant removal from pulp mill wastewater. The results suggest that this index can be used as a screening tool to rapidly process microbial fatty acid (MFA) compositional data, with the objective of making preliminary identification of underlying trends in (MFA) community structure, over time or between experimental conditions. Copyright © 2002 John Wiley & Sons, Ltd.

Brucellosis is an important public health problem in Peru. We evaluated 48 human Brucella melitensis biotype 1 strains from Peru between 2000 and 2006. MICs of isolates to doxycycline, azithromycin, gentamicin, rifampin, ciprofloxacin, and trimethoprim-sulfamethoxazole were determined by the Etest method. All isolates were sensitive to tested drugs during the periods of testing. Relapses did not appear to be related to drug resistance.

Background: Studies examining the etiology-specific effects of diarrheal disease on growth are limited and variable in their analytic methods, making comparisons difficult and priority setting based on these findings challenging. A study by Black et al (Black RE, Brown KH, Becker S. Effects of diarrhea associated with specific enteropathogens on the growth of children in rural Bangladesh. Pediatrics. 1984;33:1004–1009.) examined the association between Shigella and enterotoxigenic Escherichia coli-related disease and weight gain and linear growth in Bangladeshi children aged 0–5 years. We estimated similar associations in a 2002 cohort of 0- to 6-year-old children in the Peruvian Amazon. Methods: Diarrheal surveillence was conducted using household visits 3 times per week. Anthropometry was collected monthly. Mixed-effect models were used to estimate the association between Shigella, ETEC and Campylobacter diarrhea and weight gain in a 2-month period and linear growth over a 9-month period. Diarrheal disease burdens and growth intervals were quantified so as to be as comparable as possible to the original report. Results: Shigella- and ETEC-associated diarrhea were not associated with diminished weight gain, although the association between ETEC diarrhea and weight gain (−4.5 g/percent of days spent with ETEC, P = 0.098) was twice that of other etiologic agents, as well as similar in magnitude to the original report. Shigella-associated diarrhea was associated with decreased linear growth (0.055 cm less growth/percent days, P = 0.008), also similar to the original study. Conclusions: Our findings suggest that associations between enteropathogen-specific diarrheal episodes and growth, particularly Shigella, are comparable across geographic and epidemiological contexts.

Enhanced biological phosphorus removal (EBPR) relies on diverse but specialized microbial communities to mediate the cycling and ultimate removal of phosphorus from municipal wastewaters. However, little is known about microbial activity and dynamics in relation to process fluctuations in EBPR ecosystems. Here, we monitored temporal changes in microbial community structure and potential activity across each bioreactor zone in a pilot-scale EBPR treatment plant by examining the ratio of small subunit ribosomal RNA (SSU rRNA) to SSU rRNA gene (rDNA) over a 120 day study period. Although the majority of operational taxonomic units (OTUs) in the EBPR ecosystem were rare, many maintained high potential activities based on SSU rRNA : rDNA ratios, suggesting that rare OTUs contribute substantially to protein synthesis potential in EBPR ecosystems. Few significant differences in OTU abundance and activity were observed between bioreactor redox zones, although differences in temporal activity were observed among phylogenetically cohesive OTUs. Moreover, observed temporal activity patterns could not be explained by measured process parameters, suggesting that other ecological drivers, such as grazing or viral lysis, modulated community interactions. Taken together, these results point towards complex interactions selected for within the EBPR ecosystem and highlight a previously unrecognized functional potential among low abundance microorganisms in engineered ecosystems.

Patients recovering from traumatic injuries or surgery often require weeks to months of hospitalization, increasing the risk for wound and surgical site infections caused by ESKAPE pathogens, which include A. baumannii (the ESKAPE pathogens are Enterococcus faecium , Staphylococcus aureus , Klebsiella pneumoniae , Acinetobacter baumannii , Pseudomonas aeruginosa , and Enterobacter species). As new therapies are being developed to counter A. baumannii infections, animal models are also needed to evaluate potential treatments. Here, we present an excisional, murine wound model in which a diminutive inoculum of a clinically relevant, multidrug-resistant A. baumannii isolate can proliferate, form biofilms, and be effectively treated with antibiotics. The model requires a temporary, cyclophosphamide-induced neutropenia to establish an infection that can persist. A 6-mm-diameter, full-thickness wound was created in the skin overlying the thoracic spine, and after the wound bed was inoculated, it was covered with a dressing for 7 days. Uninoculated control wounds healed within 13 days, whereas infected, placebo-treated wounds remained unclosed beyond 21 days. Treated and untreated wounds were assessed with multiple quantitative and qualitative techniques that included gross pathology, weight loss and recovery, wound closure, bacterial burden, 16S rRNA community profiling, histopathology, peptide nucleic acid-fluorescence in situ hybridization, and scanning electron microscopy assessment of biofilms. The range of differences that we are able to identify with these measures in antibiotic- versus placebo-treated animals provides a clear window within which novel antimicrobial therapies can be assessed. The model can be used to evaluate antimicrobials for their ability to reduce specific pathogen loads in wounded tissues and clear biofilms. Ultimately, the mouse model approach allows for highly powered studies and serves as an initial multifaceted in vivo assessment prior to testing in larger animals.